This application claims the priority of German application 196 36 506.6 filed in Germany on Sep. 9, 1996, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a shift device for a gear-change transmission of a motor vehicle, comprising: a gear-shift shaft which is arranged in a gear-shift housing so as to be rotatable and axially displaceable, a shift lever which is fixed in terms of rotation relative to the gear-shift shaft and which is kinematically connected to a manual shift lever, and an additional mass which acts on the shift lever and which increases the mass moment of inertia of the gear-shift shaft in such a way that force peaks of the shifting force which is measurable on the manual shift lever are reduced during individual shifting operations.
A known gear-shift apparatus for motor vehicles (German Patent Document DE 38 39 319 C2), which corresponds to the shift device of the type mentioned in the introduction, makes use of a cab unit for receiving the shift commands of a shift lever, which is pivotable about two axes perpendicular to one another, of a transmission unit, mounted on the transmission, for sending the shift commands to the transmission and of shift cables which connect the cab unit to the transmission unit and transfer the shifting movement from the cab unit to the transmission unit, a shift-gate slot being selected by the transmission unit during a pivoting movement of the shift lever about one axis and an engaging movement for the engaging of a shift clutch being executed by the transmission unit during a pivoting movement of the shift lever about the other axis, and there being coupled to a transmission unit component executing the shifting movement a moveable actuating element, to which the shifting movement is transferred. In order to provide a gear-shift apparatus which is distinguished by an agreeable gear-shift feeling similar to that of a shift linkage, the actuating element is designed as a mass body having a mass such that, due to its inertia, it opposes appreciable resistance to the engaging movement in the initial phase of the latter and, in the end phase of the latter, by virtue of its angular momentum, appreciably assists the engaging movement and thereby partially compensates the elastic behavior of the shift cable.
German Patent Document DE 39 32 815 C2 discloses a force transfer joint for the shift linkage of a motor vehicle transmission, the joint consisting of a cardan joint cage, with a recess for the rotationally fixed mounting of a sliding block, secured therein by means of a holding member, for receiving a pin of a shift rod, of elastomeric dampers between the sliding block and the recess in the shifting directions and of a non-damped mounting of the sliding block in the recess in the selection directions. In order to avoid selection play in the selection direction and make cost-effective manufacture possible, a design is adopted to the effect that the cardan joint cage has a rectangular recess with two parallel faces and, for the selection directions, two wedge faces for receiving the correspondingly designed sliding block, a self-adjusting holding means being provided for the sliding block on the cardan joint cage.
The subject of German Patent Document DE 195 23 141 A1, not previously published, is a shift device for a gear-change transmission of a motor vehicle, with a gear-shift shaft which is arranged in a gear-shift housing so as to be rotatable and axially displaceable and which has a shift lever which is fixed in terms of rotation relative to the gear-shift shaft and which is kinematically connected to a manual shift lever, and with an additional mass which acts on the shift lever and which increases the mass moment of inertia of the gear-shift shaft in such a way that force peaks of the shifting force which is measurable on the manual shift lever are reduced during individual shifting operations. The additional mass is separately mounted pivotably relative to a housing part and is connected in transmission terms to the shift lever. The pivot-bearing axis lies parallel to the axis of rotation of the gear-shift shaft.
An object on which the invention is based consists, essentially, in a shift device of the type mentioned in the introduction, to improve further the reduction in the force peaks occurring during the shifting operation.
According to certain preferred embodiments of the invention, this object is advantageously achieved by providing a shift device for a gear-change transmission of a motor vehicle, comprising:
a gear-shift shaft which is arranged in a gear-shift housing so as to be rotatable and axially displaceable, PA1 a shift lever which is fixed in terms of rotation relative to the gear-shift shaft and which is kinematically connected to a manual shift lever, and PA1 an additional mass which acts on the shift lever and which increases the mass moment of inertia of the gear-shift shaft in such a way that force peaks of the shifting force which is measurable on the manual shift lever are reduced during individual shifting operations, PA1 wherein the kinematic connection between the shift lever and the manual shift lever has a joint with a joint half assigned as part of the connection to the shift lever and with a joint half assigned as a further part of the connection to a linkage leading to the manual shift lever, and PA1 wherein one joint half is operatively connected to that part of the connection assigned to it by means of an elastic damping member lying in the force flux of the shifting forces. PA1 a gear-shift shaft which is arranged in a gear-shift housing so as to be rotatable and axially displaceable, PA1 a shift lever which is fixed in terms of rotation relative to the gear-shift shaft and which is kinematically connected to a manual shift lever, and PA1 an additional mass which acts on the shift lever and which increases the mass moment of inertia of the gear-shift shaft in such a way that force peaks of the shifting force which is measurable on the manual shift lever are reduced during individual shifting operations, the additional mass being connected to the gear-shift shaft, and being arranged in such a way that only the engaging movement is transferred to it, PA1 wherein the additional mass is arranged on a boom which is mounted pivotably on a housing part of the gear-shift housing at a distance from the axis of rotation of the gear-shift shaft and which is connected in transmission terms to the shift lever, PA1 wherein the pivot-bearing axis of the boom lies parallel to the axis of rotation of the gear-shift shaft, PA1 wherein the kinematic connection between the shift lever and the manual shift lever has a joint with a joint half assigned as part of the connection to the shift lever and with a joint half assigned as a further part of the connection to a linkage leading to the manual shift lever, and PA1 wherein one joint half is operatively connected to that part of the connection assigned to it by means of an elastic damping member lying in the force flux of the shifting forces.
According to certain preferred embodiments of the invention, this object is advantageously achieved by providing a shift device for a gear-change transmission of a motor vehicle, comprising:
In the shift devices of the invention, both the force amplitude (the servo effect of the action of mass) and the force peaks otherwise detectable during gear shifting are reduced as a result of the influence of the additional mass. In addition, the force peaks generated during gear shifting are also eliminated by means of the elastic damping member or damping members.
Furthermore, in the shift device of the invention according to certain preferred embodiments, the dynamic effect of the additional mass is both reinforced and reliably uncoupled from the selection movements of the shift device.
In the shift devices of the invention, an optimum profile for gear-shift comfort is achieved as a result of the combination of the additional mass and damping members, as can be felt on the manual shift lever. In physical terms, the arrangement of the additional mass and damping member on the shift lever of the gear-shift shaft signifies a state in which the force effect of the mass through elasticity avoids reactions on the shift lever (force fluctuations). That is to say, the lower force fluctuations on the shift lever which have occurred during the shifting sequence can no longer be detected. This effect is also reinforced by the additional damping member in the design of the shift device of the invention according to certain preferred embodiments of the invention.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.